Selective Synthesis of Ortho-substituted 3-Cyclohexyl-2-phenyl-1,3-thiazolidin-4-one Sulfoxides and Sulfones by S-Oxidation with Oxone

Abstract

1,3-thiazolidin-4-ones, also known as thiazolidin-4-ones, are known to have a very wide range of biological activity. The corresponding S-oxides may show enhanced activity, and therefore viable synthetic routes to these S-oxides are required. S-oxidation of 3-cyclohexyl-2-phenyl-1,3-thiazolidin-4-ones with Oxone® was investigated. For all compounds evaluated, selective oxidation to the sulfoxide was realized using 3 equivalents of Oxone® at room temperature. Alternatively, the sulfone was prepared selectively at high temperature by increasing the equivalents of Oxone® used; the extent of this selectivity was affected by the substituent of the aromatic ring. In those cases in which the reaction produced a mixture of the sulfoxide and sulfone, the ratio of the products was quantified by 1H NMR.